Lab 1 Mineral Utility Lab notes
The physical world is made up of a vast number of different minerals. Later on in
the course, we will learn about some of the more common rock-forming ones. In this lab,
however, we will discuss some of the ones you have probably already heard about
because we mine them, e.g. gold, silver, and even salt or “halite”. These and most other
minerals have to be extracted from “ore” before we can use them. Nonmetallic resources
generally are not called ores, but are classified as industrial rocks and minerals. However
they still have economic significance.
Ore is any naturally occurring material from which a mineral or minerals can be
extracted profitably. An ore body is a mineral deposit or part of a mineral deposit,
consisting of ore. Ore bodies can range in size from a few tons to more than a billion
tons.
There are four major methods for collecting minerals or their ore.
Open-pits: are used for deposits within 100m or the surface. Iron, malachite and azurite
(copper), and galena (lead) are common open-pit ore minerals. Open-pits are less
selective than subsurface methods, removing massive amounts of rock for a small ore
turnover. An example of this is the Bingham Mine near Salt Lake City, Utah which
removes 225,000 metric tons of rock a day, 20% of which is ore.
Quarries: Sand, gravel and other industrial or building rocks such as limestone, granite
and marble are taken from quarries. Rocks like granite and marble are used as decorative
rocks on the outside of buildings, or even as countertops. One shell square in downtown
New Orleans is completely composed of travertine limestone.
Dredging: A special type of open pit mining used when the inflow of water is too high
to be pumped out economically, and ore is sufficiently unconsolidated to be dug without
blasting. Dredging employs chain buckets and draglines to scrape up surface deposits
covered with water. Removing mineral rich sand from a stream bed is an example of
dredging.
Subsurface mining: is used when a deposit is so deep that surface mining is impractical.
Miners dig a deep vertical shaft, blast tunnels and rooms, and transport the ore to the
surface. Compared to surface mining, proportionally more underground mining is done
in developing countries where labor costs are relatively lower.
Extremely deep ore deposits are not mineable at a profit by any method.
Processing
Minerals usually need to be processed before they can be used. Beneficiation is
the physical act of removing a mineral from its ore. Quarried rocks may simply need
crushing, grinding, and sizing before use. Metal ores require much more work to remove
impurities. Smelting and other chemical processes are used to free a metallic element
from the oxygen, sulfur, or other elements with which it is combined in an ore.
Galena’s chemical compound is PbS (lead sulfide), the chemical separation of
galena creates lead (Pb) and sulfur (S).
On the following page is an example of the total process of mineral extraction, here
specifically copper.
Environmental Concerns
There are many environmental concerns with respect to mining activities from the
initial exploration for ore to full blown extraction.
An in initial concern is cosmetics, as seen in the photo of the copper mine near silver city
an open pit mine is a major undertaking, and not necessarily aesthetically pleasing.
Mining removes habitat with the total area used by the mine including roads to transport
rock and ore through the surrounding countryside. While this may seem like a major
loss, and it is for the local area, the total land use of mines in the U.S. is only 0.26% of
the land area.
Tailings are the waste material remaining after ore has been pulverized and
concentrated for processing. Tailings contain the leftovers which can include toxic
chemicals such as sulfides. As chemicals such as sulfides mix with ground waters they
create sulfuric acid, a major component of acid rain. Sulfuric acid also works to release
even more toxic chemicals from the tailings into the environment. Leaching is the
removal of chemicals by the movement of water. This is a concern today because in the
past precautions were not taken to prevent the leaching of chemicals from tailings piles,
and these chemicals and kill an ecosystem. Today the Environmental Protection Agency
(EPA) regulates the creation and maintenance of tailings piles or ponds and requires that
they be lined with plastic or impermeable clays to prevent the leaching of chemicals into
the environment.
EES 1001- DYNAMIC EARTH LABORATORY
Lab 1 Mineral exploration and use.
Name:_______________________ Sec._______
Part I. Mineral and Rock Use
What kind of ore collection process is shown in this picture?
What collection method might be used to obtain sand for cement mixing?
Describe and discuss environmental disturbances created by a mine.
Name five parts of an automobile that are derived from minerals.
Part II. Mineral Exploration.
Materials: “Ore” Box (wooden block), straw, pipe cleaner, plastic cup.
Introduction: The purpose of this lab is to simulate the creation of a two dimensional ore map, and to calculate
the cost of ore exploration versus profit created from an ore body. When a mining company decides to explore
a possible location for a mineral ore there are a series of procedures they follow. The first is to explore the area.
This is done by taking sample cores around the area of the potential mine location. This is usually done in a
grid pattern so that the company can get a good idea of the size of the ore body. Depending on funding, the
size, and the purity of the ore body, the grid used may be in meters, or even miles. Once the approximate size
of the ore body is known the company can calculate an approximate value for the ore body. With this “value”
they can then calculate whether or not it will be profitable to mine the ore body.
Directions:
The attached page has a one inch grid on it; you will use this to create your “ore map”. There are 81
possible drill spots on the map. Your company has allotted $350,000 to the exploration of the possible Gorman
Gold ore body. One core hole costs $17,500. With your budget you have the potential to drill 20 holes.
Take the straw and stick it into one of the holes in the top of the ore box. If the straw does not hit any
ore (1/4 inch or deeper clay) and comes out empty mark the matching location on your map grid with an X,
which means no ore. If the straw comes up with “gold ore” then mark the grid intersection with an O. Pop out
the ore with the pipe cleaner and continue taking cores. Save the clay plugs you pop out in a cup provided and
turn them in when you are done with the box. Remember your budget limits you to selecting 20 core locations
to map the ore body. (Note: The straw may come up with a small amount of clay, less than a millimeter or two
thick, if it does then still consider this to contain no ore. Only if the straw comes up with approximately a
quarter of an inch or more of clay should you consider the “core location” to contain “ore”. Also, try twisting
or rotating the straw as you push it in, this way you will not get a false negative. I.e. The straw comes out
empty when it should not.)
When you have taken 20 cores, take your grid map and draw a circle around the core locations where
you found ore. You now have an approximate map of the Gorman ore body.
1. If one inch on your map is equal to 110 yards, calculate the approximate size (area) of the Gorman Gold
ore body. (hint one square on the map is 12,100 square yards)
2. Each square yard of rock you mine will produce 3 tons of ore. How many tons of ore will the Gorman
gold ore body produce?
3. Each ton of ore will produce 4 grams of gold, and a gram of gold is worth approximately $12.00. How
much money will the Gorman mine produce?
4. It costs $2 to mine a square yard of rock, and another $3 per square yard of rock for transportation and
processing of the ore rock. What is the cost of mining and processing the ore? What is the cost if we
include the cost of the exploration? will it be economical for the company to mine the Gorman Gold ore
body? How much profit will be made from the Gorman Gold ore body if any is at all?
block number ________
N
x- no ore found o- ore found
|
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110 yds